I can vouch for the 210 being a very “listenable” receiver,(my fave). Keep in mind it is “only” 10 meager watts. Although those 10 watts are sweet, you will need efficient speakers, a small room, or both. It is a very simple design, perhaps that accounts for some of the sonic bliss.
I have the AU505, the bigger sibling to the AU101, whilst it too sounds good, there is something about the 210 that the 505 just doesn’t have. I have transitioned to tubes, and the 210 is extremely close to that sound, not quite, but the closest thing I’ve heard.
Good luck with the search, and the old cliche still stands, “all Sansuis sound good, just have different flavors”. Isn’t this fun!!